Adjuvant-sparing multi-dose influenza vaccination regimen

ABSTRACT

An influenza vaccine is administered by a multi-dose regimen, in which (i) a first dose is administered with an adjuvant and (ii) a later dose is administered either without an adjuvant or with a different adjuvant. Thus the invention provides the benefits of a two-dose regimen without also doubling the supply need for a given adjuvant.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of patent application of U.S. patentapplication Ser. No. 12/304,919, which is the national phase ofInternational Application PCT/IB2007/002724, with a filing date of Jun.15, 2007, which claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/814,665, with a filing date of Jun. 15, 2006,all of which are incorporated herein by reference in their entirety.

TECHNICAL FIELD

This invention is in the field of vaccines for protecting againstinfluenza virus infection.

BACKGROUND ART

Patients receiving influenza vaccines are currently given one dose everyyear, except that the first time that the vaccine is given to a childaged 8 years or below they receive two doses separated by at least fourweeks.

It is thought (e.g. see ref. 1) that a two-dose regimen will also berequired in a pandemic situation, where the human population isimmunologically naïve to a new influenza virus strain.

The need for two doses means that, with a fixed supply of antigen, thenumber of doses that can be made is half of the number that could bemade with a one-dose regimen. Thus it has been proposed to use a loweramount of antigen per dose, and to use an adjuvant to compensate forthis reduction.

If a one-dose regimen of an adjuvanted vaccine does not elicit asufficient immune response, however, then a two-dose regimen will berequired anyway, with the additional disadvantage that the supply ofadequate amounts of adjuvant will also then be an issue. In a situationwhere hundreds of millions of adjuvanted vaccine doses are beingprepared then this issue will be very important, and will beparticularly important for synthetic adjuvants.

It is an object of the invention to reduce or avoid this disadvantage.

DISCLOSURE OF THE INVENTION

According to the invention, an influenza vaccine is administered by amulti-dose regimen, in which (i) a first dose is administered with anadjuvant and (ii) a later dose is administered either without anadjuvant or with a different adjuvant. Thus the invention provides thebenefits of a two-dose regimen without also doubling the supply need fora given adjuvant. The first dose and the later dose should preferablygiven by the same administration route (e.g. both by intramuscularinjection), whereas the study in reference 2 used an unadjuvantedmucosal booster as a third dose in a three-dose regimen in order todetermine whether the parenteral priming route in mice (back vs. neck)affected the immunogenicity of an adjuvanted vaccine.

Thus the invention provides a method for immunizing a patient againstinfluenza virus infection, comprising the steps of: (i) administering adose of influenza virus vaccine in combination with a first adjuvant;and (ii) administering a further dose of influenza virus vaccine withoutthat adjuvant. The further dose may include no adjuvant or may include asecond adjuvant that is different from the first adjuvant.

The invention also provides a kit comprising: (i) a first influenzavirus vaccine in combination with a first adjuvant; and (ii) a secondinfluenza virus vaccine without that adjuvant. The invention alsoprovides the use of (i) a first influenza virus vaccine in combinationwith a first adjuvant; and (ii) a second influenza virus vaccine withoutthat adjuvant, in the manufacture of a multi-dose influenza vaccine. Thesecond vaccine may include no adjuvant or may include a second adjuvantthat is different from the first adjuvant.

The invention also provides a method for completing the immunization ofa patient against influenza virus infection, wherein the patient haspreviously received a dose of influenza virus vaccine in combinationwith a first adjuvant, and wherein the method comprises the step ofadministering to that patient a further dose of influenza virus vaccinewithout that adjuvant. The further dose may include no adjuvant or mayinclude a second adjuvant that is different from the first adjuvant.

The invention also provides the use of an unadjuvanted influenza virusvaccine in the manufacture of a medicament for immunizing a patientagainst influenza virus infection, wherein that patient has previouslyreceived an adjuvanted influenza virus vaccine. The invention alsoprovides the use of a second adjuvanted influenza virus vaccine in themanufacture of a medicament for immunizing a patient against influenzavirus infection, wherein that patient has previously received a firstadjuvanted influenza virus vaccine, wherein the adjuvants in the firstand second influenza virus are not the same.

These methods, kits and uses are particularly advantageous if thehemagglutinin doses in the two vaccinations are lower than the standard15 μg per strain per dose, as the invention then permits relaxation ofrequirements for both antigen and adjuvant.

The Influenza Virus Antigen

Vaccines used with the invention include an influenza virus antigen. Theantigen will typically be prepared from influenza virions but, as analternative, antigens such as haemagglutinin and neuraminidase can beexpressed in a recombinant host (e.g. in an insect cell line using abaculovirus vector) and used in purified form [3, 4, 5]. In general,however, antigens will be from virions.

The antigen may take the form of a live virus or, more preferably, aninactivated virus. Chemical means for inactivating a virus includetreatment with an effective amount of one or more of the followingagents: detergents, formaldehyde, formalin, β-propiolactone, or UVlight. Additional chemical means for inactivation include treatment withmethylene blue, psoralen, carboxyfullerene (C60) or a combination of anythereof. Other methods of viral inactivation are known in the art, suchas for example binary ethylamine, acetyl ethyleneimine, or gammairradiation. The INFLEXAL™ product is a whole virion inactivatedvaccine.

Where an inactivated virus is used, the vaccine may comprise wholevirion, split virion, or purified surface antigens (includinghemagglutinin and, usually, also including neuraminidase).

Typically, each vaccine dose in a multi-dose regimen will use the sameform of antigen e.g. it will not use a split virion vaccine for a firstdose and a whole virion vaccine for a second dose.

Virions can be harvested from virus-containing fluids by variousmethods. For example, a purification process may involve zonalcentrifugation using a linear sucrose gradient solution that includesdetergent to disrupt the virions. Antigens may then be purified, afteroptional dilution, by diafiltration.

Split virions are obtained by treating virions with detergents (e.g.ethyl ether, polysorbate 80, deoxycholate, tri-N-butyl phosphate, TritonX-100, Triton N101, cetyltrimethylammonium bromide, Tergitol NP9, etc.)to produce subvirion preparations, including the ‘Tween-ether’ splittingprocess. Methods of splitting influenza viruses are well known in theart e.g. see refs. 6-11, etc. Splitting of the virus is typicallycarried out by disrupting or fragmenting whole virus, whether infectiousor non-infectious with a disrupting concentration of a splitting agent.The disruption results in a full or partial solubilisation of the virusproteins, altering the integrity of the virus. Preferred splittingagents are non-ionic and ionic (e.g. cationic) surfactants e.g.alkylglycosides, alkylthioglycosides, acyl sugars, sulphobetaines,betains, polyoxyethylenealkylethers, N,N-dialkyl-Glucamides, Hecameg,alkylphenoxy-polyethoxyethanols, quaternary ammonium compounds,sarcosyl, CTABs (cetyl trimethyl ammonium bromides), tri-N-butylphosphate, Cetavlon, myristyltrimethylammonium salts, lipofectin,lipofectamine, and DOT-MA, the octyl- or nonylphenoxy polyoxyethanols(e.g. the Triton surfactants, such as Triton X-100 or Triton N101),polyoxyethylene sorbitan esters (the Tween surfactants), polyoxyethyleneethers, polyoxyethlene esters, etc. One useful splitting procedure usesthe consecutive effects of sodium deoxycholate and formaldehyde, andsplitting can take place during initial virion purification (e.g. in asucrose density gradient solution). Thus a splitting process can involveclarification of the virion-containing material (to remove non-virionmaterial), concentration of the harvested virions (e.g. using anadsorption method, such as CaHPO₄ adsorption), separation of wholevirions from non-virion material, splitting of virions using a splittingagent in a density gradient centrifugation step (e.g. using a sucrosegradient that contains a splitting agent such as sodium deoxycholate),and then filtration (e.g. ultrafiltration) to remove undesiredmaterials. Split virions can usefully be resuspended in sodiumphosphate-buffered isotonic sodium chloride solution. The BEGRIVAC™,FLUARIX™, FLUZONE™ and FLUSHIELD™ products are split vaccines.

Purified surface antigen vaccines comprise the influenza surfaceantigens haemagglutinin and, typically, also neuraminidase. Processesfor preparing these proteins in purified form are well known in the art.The FLUVIRIN™, AGRIPPAL™ and INFLUVAC™ products are subunit vaccines.

Influenza antigens can also be presented in the form of virosomes [12](nucleic acid free viral-like liposomal particles), as in the INFLEXALV™ and INVAVAC™ products, but it is preferred not to use virosomes withthe present invention. Thus, in some embodiments, the influenza antigenis not in the form of a virosome.

The influenza virus may be attenuated. The influenza virus may betemperature-sensitive. The influenza virus may be cold-adapted. Thesethree features are particularly useful when using live virus as anantigen.

Influenza virus strains for use in vaccines change from season toseason. In the current inter-pandemic period, vaccines typically includetwo influenza A strains (H1N1 and H3N2) and one influenza B strain, andtrivalent vaccines are typical. The invention can be use with thesevaccines, but is particularly useful for viruses from pandemic strains(i.e. strains to which the vaccine recipient and the general humanpopulation are immunologically naïve), such as H2, H5, H7 or H9 subtypestrains (in particular of influenza A virus), and influenza vaccines forpandemic strains may be monovalent or may be based on a normal trivalentvaccine supplemented by a pandemic strain. Depending on the season andon the nature of the antigen included in the vaccine, however, theinvention may protect against one or more of influenza A virushemagglutinin subtypes H1, H2, H3, H4, H5, H6, H7, H8, H9, H10, H11,H12, H13, H14, H15 or H16. The invention may protect against one or moreof influenza A virus NA subtypes N1, N2, N3, N4, N5, N6, N7, N8 or N9.

Other strains that can usefully be included in the compositions arestrains which are resistant to antiviral therapy (e.g. resistant tooseltamivir [13] and/or zanamivir), including resistant pandemic strains[14].

The invention is particularly useful for immunizing against pandemicstrains. The characteristics of an influenza strain that give it thepotential to cause a pandemic outbreak are: (a) it contains a newhemagglutinin compared to the hemagglutinins in currently-circulatinghuman strains, i.e. one that has not been evident in the humanpopulation for over a decade (e.g. H2), or has not previously been seenat all in the human population (e.g. H5, H6 or H9, that have generallybeen found only in bird populations), such that the human populationwill be immunologically naïve to the strain's hemagglutinin; (b) it iscapable of being transmitted horizontally in the human population; and(c) it is pathogenic to humans. A virus with H5 haemagglutinin type ispreferred for immunizing against pandemic influenza, such as a H5N1strain. Other possible strains include H5N3, H9N2, H2N2, H7N1 and H7N7,and any other emerging potentially pandemic strains. Within the H5subtype, a virus may fall into HA clade 1, HA clade 1′, HA clade 2 or HAclade 3 [15], with clades 1 and 3 being particularly relevant.

Typically, each vaccine dose in a multi-dose regimen will share at leastone common hemagglutinin subtype e.g. the invention will not use amonovalent H5N1 vaccine for a first dose but a monovalent H9N2 vaccinefor a second dose.

Compositions of the invention may include antigen(s) from one or more(e.g. 1, 2, 3, 4 or more) influenza virus strains, including influenza Avirus and/or influenza B virus. Where a vaccine includes more than onestrain of influenza, the different strains are typically grownseparately and are mixed after the viruses have been harvested andantigens have been prepared. Thus a process of the invention may includethe step of mixing antigens from more than one influenza strain. Forpandemic situations, however, a monovalent vaccine may be preferred.

The influenza virus may be a reassortant strain, and may have beenobtained by reverse genetics techniques. Reverse genetics techniques[e.g. 16-20] allow influenza viruses with desired genome segments to beprepared in vitro using plasmids. Typically, it involves expressing (a)DNA molecules that encode desired viral RNA molecules e.g. from polIpromoters, and (b) DNA molecules that encode viral proteins e.g. frompolII promoters, such that expression of both types of DNA in a cellleads to assembly of a complete intact infectious virion. The DNApreferably provides all of the viral RNA and proteins, but it is alsopossible to use a helper virus to provide some of the RNA and proteins.Plasmid-based methods using separate plasmids for producing each viralRNA are preferred [21-23], and these methods will also involve the useof plasmids to express all or some (e.g. just the PB1, PB2, PA and NPproteins) of the viral proteins, with up to 12 plasmids being used insome methods.

To reduce the number of plasmids needed, a recent approach [24] combinesa plurality of RNA polymerase I transcription cassettes (for viral RNAsynthesis) on the same plasmid (e.g. sequences encoding 1, 2, 3, 4, 5,6, 7 or all 8 influenza A vRNA segments), and a plurality ofprotein-coding regions with RNA polymerase II promoters on anotherplasmid (e.g. sequences encoding 1, 2, 3, 4, 5, 6, 7 or all 8 influenzaA mRNA transcripts). Preferred aspects of the reference 24 methodinvolve: (a) PB1, PB2 and PA mRNA-encoding regions on a single plasmid;and (b) all 8 vRNA-encoding segments on a single plasmid. Including theNA and HA segments on one plasmid and the six other segments on anotherplasmid can also facilitate matters.

As an alternative to using polI promoters to encode the viral RNAsegments, it is possible to use bacteriophage polymerase promoters [25].For instance, promoters for the SP6, T3 or T7 polymerases canconveniently be used. Because of the species-specificity of polIpromoters, bacteriophage polymerase promoters can be more convenient formany cell types (e.g. MDCK), although a cell must also be transfectedwith a plasmid encoding the exogenous polymerase enzyme.

In other techniques it is possible to use dual polI and polII promotersto simultaneously code for the viral RNAs and for expressible mRNAs froma single template [26, 27].

Thus the virus, particularly an influenza A virus, may include one ormore RNA segments from a A/PR/8/34 virus (typically 6 segments fromA/PR/8/34, with the HA and N segments being from a vaccine strain, i.e.a 6:2 reassortant), particularly when viruses are grown in eggs. It mayalso include one or more RNA segments from a A/WSN/33 virus, or from anyother virus strain useful for generating reassortant viruses for vaccinepreparation. Typically, the invention protects against a strain that iscapable of human-to-human transmission, and so the strain's genome willusually include at least one RNA segment that originated in a mammalian(e.g. in a human) influenza virus. It may include NS segment thatoriginated in an avian influenza virus.

The viruses used as the source of the antigens can be grown either oneggs or on cell culture. The current standard method for influenza virusgrowth uses specific pathogen-free (SPF) embryonated hen eggs, withvirus being purified from the egg contents (allantoic fluid). Morerecently, however, viruses have been grown in animal cell culture and,for reasons of speed and patient allergies, this growth method ispreferred. If egg-based viral growth is used then one or more aminoacids may be introduced into the allantoid fluid of the egg togetherwith the virus [11].

When cell culture is used, the viral growth substrate will typically bea cell line of mammalian origin. Suitable mammalian cells of origininclude, but are not limited to, hamster, cattle, primate (includinghumans and monkeys) and dog cells. Various cell types may be used, suchas kidney cells, fibroblasts, retinal cells, lung cells, etc. Examplesof suitable hamster cells are the cell lines having the names BHK21 orHKCC. Suitable monkey cells are e.g. African green monkey cells, such askidney cells as in the Vero cell line. Suitable dog cells are e.g.kidney cells, as in the MDCK cell line. Thus suitable cell linesinclude, but are not limited to: MDCK; CHO; 293T; BHK; Vero; MRC-5;PER.C6; WI-38; etc. Preferred mammalian cell lines for growing influenzaviruses include: MDCK cells [28-31], derived from Madin Darby caninekidney; Vero cells [32-34], derived from African green monkey(Cercopithecus aethiops) kidney; or PER.C6 cells [35], derived fromhuman embryonic retinoblasts. These cell lines are widely available e.g.from the American Type Cell Culture (ATCC) collection [36], from theCoriell Cell Repositories [37], or from the European Collection of CellCultures (ECACC). For example, the ATCC supplies various different Verocells under catalog numbers CCL-81, CCL-81.2, CRL-1586 and CRL-1587, andit supplies MDCK cells under catalog number CCL-34. PER.C6 is availablefrom the ECACC under deposit number 96022940. As a less-preferredalternative to mammalian cell lines, virus can be grown on avian celllines [e.g. refs. 38-40], including cell lines derived from ducks (e.g.duck retina) or hens. Examples of avian cell lines include avianembryonic stem cells [38, 41] and duck retina cells [39]. Suitable avianembryonic stem cells, include the EBx cell line derived from chickenembryonic stem cells, EB45, EB14, and EB14-074 [42]. Chicken embryofibroblasts (CEF) may also be used.

The most preferred cell lines for growing influenza viruses are MDCKcell lines. The original MDCK cell line is available from the ATCC asCCL-34, but derivatives of this cell line may also be used. Forinstance, reference 28 discloses a MDCK cell line that was adapted forgrowth in suspension culture (‘MDCK 33016’, deposited as DSM ACC 2219).Similarly, reference 43 discloses a MDCK-derived cell line that grows insuspension in serum-free culture (‘B-702’, deposited as FERM BP-7449).Reference 44 discloses non-tumorigenic MDCK cells, including ‘MDCK-S’(ATCC PTA-6500), ‘MDCK-SF101’ (ATCC PTA-6501), ‘MDCK-SF102’ (ATCCPTA-6502) and ‘MDCK-SF103’ (PTA-6503). Reference 45 discloses MDCK celllines with high susceptibility to infection, including ‘MDCK.5F1’ cells(ATCC CRL-12042). Any of these MDCK cell lines can be used.

Where virus has been grown on a mammalian cell line then the compositionwill advantageously be free from egg proteins (e.g. ovalbumin andovomucoid) and from chicken DNA, thereby reducing allergenicity.

Where virus has been grown on a cell line then the culture for growth,and also the viral inoculum used to start the culture, will preferablybe free from (i.e. will have been tested for and given a negative resultfor contamination by) herpes simplex virus, respiratory syncytial virus,parainfluenza virus 3, SARS coronavirus, adenovirus, rhinovirus,reoviruses, polyomaviruses, bimaviruses, circoviruses, and/orparvoviruses [46]. Absence of herpes simplex viruses is particularlypreferred.

For growth on a cell line, such as on MDCK cells, virus may be grown oncells in suspension [47-49] or in adherent culture. One suitable MDCKcell line for suspension culture is MDCK 33016 (deposited as DSM ACC2219). As an alternative, microcarrier culture can be used.

Cell lines supporting influenza virus replication are preferably grownin serum-free culture media and/or protein free media. A medium isreferred to as a serum-free medium in the context of the presentinvention in which there are no additives from serum of human or animalorigin. Protein-free is understood to mean cultures in whichmultiplication of the cells occurs with exclusion of proteins, growthfactors, other protein additives and non-serum proteins, but canoptionally include proteins such as trypsin or other proteases that maybe necessary for viral growth. The cells growing in such culturesnaturally contain proteins themselves.

Cell lines supporting influenza virus replication are preferably grownbelow 37° C. [50] during viral replication e.g. 30-36° C.

The method for propagating virus in cultured cells generally includesthe steps of inoculating the cultured cells with the strain to becultured, cultivating the infected cells for a desired time period forvirus propagation, such as for example as determined by virus titer orantigen expression (e.g. between 24 and 168 hours after inoculation) andcollecting the propagated virus. The cultured cells are inoculated witha virus (measured by PFU or TCID₅₀) to cell ratio of 1:500 to 1:1,preferably 1:100 to 1:5, more preferably 1:50 to 1:10. The virus isadded to a suspension of the cells or is applied to a monolayer of thecells, and the virus is absorbed on the cells for at least 60 minutesbut usually less than 300 minutes, preferably between 90 and 240 minutesat 25° C. to 40° C., preferably 28° C. to 37° C. The infected cellculture (e.g. monolayers) may be removed either by freeze-thawing or byenzymatic action to increase the viral content of the harvested culturesupernatants. The harvested fluids are then either inactivated or storedfrozen. Cultured cells may be infected at a multiplicity of infection(“m.o.i.”) of about 0.0001 to 10, preferably 0.002 to 5, more preferablyto 0.001 to 2. Still more preferably, the cells are infected at a m.o.iof about 0.01. Infected cells may be harvested 30 to 60 hours postinfection. Preferably, the cells are harvested 34 to 48 hours postinfection. Still more preferably, the cells are harvested 38 to 40 hourspost infection. Proteases (typically trypsin) are generally added duringcell culture to allow viral release, and the proteases can be added atany suitable stage during the culture.

Haemagglutinin (HA) is the main immunogen in inactivated influenzavaccines, and vaccine doses are standardised by reference to HA levels,typically as measured by a single radial immunodiffusion (SRID) assay.Current vaccines typically contain about 15 μg of HA per strain,although lower doses are also used e.g. for children, or in pandemicsituations. Fractional doses such as ½ (i.e. 7.5 μg HA per strain), ¼and ⅛ have been used [51, 52], as have higher doses (e.g. 3× or 9× doses[53, 54]).Thus vaccines may include between 0.1 and 150 μg of HA perinfluenza strain, preferably between 0.1 and 50 μg e.g. 0.1-20 μg,0.1-15 μg, 0.1-10 μg, 0.1-7.5 μg, 0.5-5 μg, etc. Particular dosesinclude e.g. about 45, about 30, about 15, about 10, about 7.5, about 5,about 3.8, about 1.9, about 1.5, etc. μg per strain. These lower dosesare most useful when an adjuvant is present in the vaccine, as with theinvention.

For live vaccines, dosing is measured by median tissue cultureinfectious dose (TCID₅₀) rather than HA content, and a TCID₅₀ of between10⁶ and 10⁸ (preferably between 10^(6.5)-10^(7.5)) per strain istypical.

HA used with the invention may be a natural HA as found in a virus, ormay have been modified. For instance, it is known to modify HA to removedeterminants (e.g. hyper-basic regions around the cleavage site betweenHA1 and HA2) that cause a virus to be highly pathogenic in avianspecies, as these determinants can otherwise prevent a virus from beinggrown in eggs.

Compositions of the invention may include detergent e.g. apolyoxyethylene sorbitan ester surfactant (known as ‘Tweens’), anoctoxynol (such as octoxynol-9 (Triton X-100) ort-octylphenoxypolyethoxyethanol), a cetyl trimethyl ammonium bromide(‘CTAB’), or sodium deoxycholate, particularly for a split or surfaceantigen vaccine. The detergent may be present only at trace amounts.Thus the vaccine may included less than 1 mg/ml of each of octoxynol-10,α-tocopheryl hydrogen succinate and polysorbate 80. Other residualcomponents in trace amounts could be antibiotics (e.g. neomycin,kanamycin, polymyxin B).

An inactivated but non-whole cell vaccine (e.g. a split virus vaccine ora purified surface antigen vaccine) may include matrix protein, in orderto benefit from the additional T cell epitopes that are located withinthis antigen. Thus a non-whole cell vaccine (particularly a splitvaccine) that includes haemagglutinin and neuraminidase may additionallyinclude M1 and/or M2 matrix protein, or fragment(s) thereof. Where amatrix protein is present, inclusion of detectable levels of M1 matrixprotein is preferred. Nucleoprotein may also be present.

Host Cell DNA

Where virus has been grown on a cell line then it is standard practiceto minimize the amount of residual cell line DNA in the final vaccine,in order to minimize any oncogenic activity of the DNA. Thus, wherevirus has been grown on a cell line, the composition preferably containsless than 10 ng (preferably less than 1 ng, and more preferably lessthan 100 pg) of residual host cell DNA per dose, although trace amountsof host cell DNA may be present. It is preferred that the average lengthof any residual host cell DNA is less than 500 bp e.g. less than 400 bp,less than 300 bp, less than 200 bp, less than 100 bp, etc. In general,the host cell DNA that it is desirable to exclude from compositions ofthe invention is DNA that is longer than 100 bp.

Measurement of residual host cell DNA is now a routine regulatoryrequirement for biologicals and is within the normal capabilities of theskilled person. The assay used to measure DNA will typically be avalidated assay [55, 56]. The performance characteristics of a validatedassay can be described in mathematical and quantifiable terms, and itspossible sources of error will have been identified. The assay willgenerally have been tested for characteristics such as accuracy,precision, specificity. Once an assay has been calibrated (e.g. againstknown standard quantities of host cell DNA) and tested then quantitativeDNA measurements can be routinely performed. Three principle techniquesfor DNA quantification can be used: hybridization methods, such asSouthern blots or slot blots [57]; immunoassay methods, such as theThreshold™ System [58]; and quantitative PCR [59]. These methods are allfamiliar to the skilled person, although the precise characteristics ofeach method may depend on the host cell in question e.g. the choice ofprobes for hybridization, the choice of primers and/or probes foramplification, etc. The Threshold™ system from Molecular Devices is aquantitative assay for picogram levels of total DNA, and has been usedfor monitoring levels of contaminating DNA in biopharmaceuticals [58]. Atypical assay involves non-sequence-specific formation of a reactioncomplex between a biotinylated ssDNA binding protein, aurease-conjugated anti-ssDNA antibody, and DNA. All assay components areincluded in the complete Total DNA Assay Kit available from themanufacturer. Various commercial manufacturers offer quantitative PCRassays for detecting residual host cell DNA e.g. AppTec™ LaboratoryServices, BioReliance™, Althea Technologies, etc. A comparison of achemiluminescent hybridisation assay and the total DNA Threshold™ systemfor measuring host cell DNA contamination of a human viral vaccine canbe found in reference 60.

Contaminating DNA can be removed during vaccine preparation usingstandard purification procedures e.g. chromatography, etc. Removal ofresidual host cell DNA can be enhanced by nuclease treatment e.g. byusing a DNase. A convenient method for reducing host cell DNAcontamination is disclosed in references 61 & 62, involving a two-steptreatment, first using a DNase (e.g. Benzonase), which may be usedduring viral growth, and then a cationic detergent (e.g. CTAB), whichmay be used during virion disruption. Treatment with an alkylatingagent, such as β-propiolactone, can also be used to remove host cellDNA, and advantageously may also be used to inactivate virions [63].

Vaccines containing <10 ng (e.g. <1 ng, <100 pg) host cell DNA per 15 μgof haemagglutinin are preferred, as are vaccines containing <10 ng (e.g.<1 ng, <100 pg) host cell DNA per 0.25 ml volume. Vaccines containing<10 ng (e.g. <1 ng, <100 pg) host cell DNA per 50 μg of haemagglutininare more preferred, as are vaccines containing <10 ng (e.g. <1 ng, <100pg) host cell DNA per 0.5 ml volume.

The Adjuvant(s)

The invention involves the initial administration of an adjuvantedvaccine. Further vaccines may be unadjuvanted, or they may be adjuvantedbut with a different adjuvant from the initial administration. Theadjuvant(s) can function to enhance the immune responses (humoral and/orcellular) elicited in a patient who receives the composition.

Suitable adjuvants for use with the first vaccine, and for optional usewith further vaccine dose(s), include, but are not limited to:

-   -   A mineral-containing composition, including calcium salts and        aluminum salts (or mixtures thereof). Calcium salts include        calcium phosphate (e.g. the “CAP” particles disclosed in ref.        64). Aluminum salts include hydroxides, phosphates, sulfates,        etc., with the salts taking any suitable form (e.g. gel,        crystalline, amorphous, etc.). Adsorption to these salts is        preferred. The mineral containing compositions may also be        formulated as a particle of metal salt [65]. Aluminum salt        adjuvants are described in more detail below.    -   An oil-in-water emulsion, as described in more detail below.    -   An immunostimulatory oligonucleotide, as described in more        detail below.    -   3-O-deacylated monophosphoryl lipid A (‘3dMPL’, also known as        ‘MPL™’), as described in more detail below.    -   An imidazoquinoline compound, such as Imiquimod (“R-837”) [66,        67], Resiquimod (“R-848”) [68], and their analogs; and salts        thereof (e.g. the hydrochloride salts). Further details about        immunostimulatory imidazoquinolines can be found in references        69 to 73.    -   A thiosemicarbazone compound, such as those disclosed in        reference 74. Methods of formulating, manufacturing, and        screening for active compounds are also described in        reference 74. The thiosemicarbazones are particularly effective        in the stimulation of human peripheral blood mononuclear cells        for the production of cytokines, such as TNF-α.    -   A nucleoside analog, such as: (a) Isatorabine (ANA-245;        7-thia-8-oxoguanosine):

-   -    and prodrugs thereof; (b) ANA975; (c) ANA-025-1; (d)        ANA380; (e) the compounds disclosed in references 75 to 77; (f)        a compound having the formula:

-   -   -   wherein:            -   R₁ and R₂ are each independently H, halo, —NR_(a)R_(b),                —OH, C₁₋₆ alkoxy, substituted C₁₋₆ alkoxy, heterocyclyl,                substituted heterocyclyl, C₆₋₁₀ aryl, substituted C₆₋₁₀                aryl, C₁₋₆ alkyl, or substituted C₁₋₆ alkyl;            -   R₃ is absent, H, C₁₋₆ alkyl, substituted C₁₋₆ alkyl,                C₆₋₁₀ aryl, substituted C₆₋₁₀ aryl, heterocyclyl, or                substituted heterocyclyl;            -   R₄ and R₅ are each independently H, halo, heterocyclyl,                substituted heterocyclyl, —C(O)—R_(d), C₁₋₆ alkyl,                substituted C₁₋₆ alkyl, or bound together to form a 5                membered ring as in R₄₋₅:

-   -   -   -   -   the binding being achieved at the bonds indicated by                    a

            -   X₁ and X₂ are each independently N, C, O, or S;

            -   R₈ is H, halo, —OH, C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆                alkynyl, —OH, —NR_(a)R_(b), —(CH₂)_(n)—O—R_(c), —O—(C₁₋₆                alkyl), —S(O)_(p)R_(e), or —C(O)—R_(d);

            -   R₉ is H, C₁₋₆ alkyl, substituted C₁₋₆ alkyl,                heterocyclyl, substituted heterocyclyl or R_(9a),                wherein R_(9a) is:

-   -   -   -   -   the binding being achieved at the bond indicated by                    a

            -   R₁₀ and R₁₁ are each independently H, halo, C₁₋₆ alkoxy,                substituted C₁₋₆ alkoxy, —NR_(a)R_(b), or —OH;

            -   each R_(a) and R_(b) is independently H, C₁₋₆ alkyl,                substituted C₁₋₆ alkyl, —C(O)R_(d), C₆₋₁₀ aryl;

            -   each R_(c) is independently H, phosphate, diphosphate,                triphosphate, C₁₋₆ alkyl, or substituted C₁₋₆ alkyl;

            -   each R_(d) is independently H, halo, C₁₋₆ alkyl,                substituted C₁₋₆ alkyl, C₁₋₆ alkoxy, substituted C₁₋₆                alkoxy, —NH₂, —NH(C₁₋₆ alkyl), —NH (substituted C₁₋₆                alkyl), —N(C₁₋₆ alkyl)₂, —N(substituted C₁₋₆ alkyl)₂,                C₆₋₁₀ aryl, or heterocyclyl;

            -   each R_(e) is independently H, C₁₋₆ alkyl, substituted                C₁₋₆ alkyl, C₆₋₁₀ aryl, substituted C₆₋₁₀ aryl,                heterocyclyl, or substituted heterocyclyl;

            -   each R_(f) is independently H, C₁₋₆ alkyl, substituted                C₁₋₆ alkyl, —C(O)R_(d), phosphate, diphosphate, or                triphosphate;

            -   each n is independently 0, 1, 2, or 3;

            -   each p is independently 0, 1, or 2; or

    -    or (g) a pharmaceutically acceptable salt of any of (a) to (f),        a tautomer of any of (a) to (f), or a pharmaceutically        acceptable salt of the tautomer.

    -   A tryptanthrin compound, such as those disclosed in        reference 78. Methods of formulating, manufacturing, and        screening for active compounds are also described in        reference 78. The thiosemicarbazones are particularly effective        in the stimulation of human peripheral blood mononuclear cells        for the production of cytokines, such as TNF-α.

    -   Loxoribine (7-allyl-8-oxoguanosine) [79].

    -   Compounds disclosed in reference 80, including: Acylpiperazine        compounds, Indoledione compounds, Tetrahydraisoquinoline (THIQ)        compounds, Benzocyclodione compounds, Aminoazavinyl compounds,        Aminobenzimidazole quinolinone (ABIQ) compounds [81, 82],        Hydrapthalamide compounds, Benzophenone compounds, Isoxazole        compounds, Sterol compounds, Quinazilinone compounds, Pyrrole        compounds [83], Anthraquinone compounds, Quinoxaline compounds,        Triazine compounds, Pyrazalopyrimidine compounds, and Benzazole        compounds [84].

    -   Compounds disclosed in reference 85, including        3,4-di(1H-indol-3-yl)-1H-pyrrole-2,5-diones, staurosporine        analogs, derivatized pyridazines, chromen-4-ones, indolinones,        quinazolines, and nucleoside analogs.

    -   An aminoalkyl glucosaminide phosphate derivative, such as RC-529        [86, 87].

    -   A phosphazene, such as poly[di(carboxylatophenoxy)phosphazene]        (“PCPP”) as described, for example, in references 88 and 89.

    -   Small molecule immunopotentiators (SMIPs) such as:

-   N2-methyl-1-(2-methylpropyl)-1H-imidazo[4,5-c]quinoline-2,4-diamine

-   N2,N2-dimethyl-1-(2-methylpropyl)-1H-imidazo[4,5-c]quinoline-2,4-diamine

-   N2-ethyl-N2-methyl-1-(2-methylpropyl)-1H-imidazo[4,5-c]quinoline-2,4-diamine

-   N2-methyl-1-(2-methylpropyl)-N2-propyl-1H-imidazo[4,5-c]quinoline-2,4-diamine

-   1-(2-methylpropyl)-N2-propyl-1H-imidazo[4,5-c]quinoline-2,4-diamine

-   N2-butyl-1-(2-methylpropyl)-1H-imidazo[4,5-c]quinoline-2,4-diamine

-   N2-butyl-N2-methyl-1-(2-methylpropyl)-1H-imidazo[4,5-c]quinoline-2,4-diamine

-   N2-methyl-1-(2-methylpropyl)-N2-pentyl-1H-imidazo[4,5-c]quinoline-2,4-diamine

-   N2-methyl-1-(2-methylpropyl)-N2-prop-2-enyl-1H-imidazo[4,5-c]quinoline-2,4-diamine

-   1-(2-methylpropyl)-2-[(phenylmethyl)thio]-1H-imidazo[4,5-c]quinolin-4-amine

-   1-(2-methylpropyl)-2-(propylthio)-1H-imidazo[4,5-c]quinolin-4-amine

-   2-[[4-amino-1-(2-methylpropyl)-1H-imidazo[4,5-c]quinolin-2-yl](methyl)amino]ethanol

-   2-[[4-amino-1-(2-methylpropyl)-1H-imidazo[4,5-c]quinolin-2-yl](methyl)amino]ethyl    acetate

-   4-amino-1-(2-methylpropyl)-1,3-dihydro-2H-imidazo[4,5-c]quinolin-2-one

-   N2-butyl-1-(2-methylpropyl)-N4,N4-bis(phenylmethyl)-1H-imidazo[4,5-c]quinoline-2,4-diamine

-   N2-butyl-N2-methyl-1-(2-methylpropyl)-N4,N4-bis(phenylmethyl)-1H-imidazo[4,5-c]quinoline-2,4-diamine

-   N2-methyl-1-(2-methylpropyl)-N4,N4-bis(phenylmethyl)-1H-imidazo[4,5-c]quinoline-2,4-diamine

-   N2,N2-dimethyl-1-(2-methylpropyl)-N4,N4-bis(phenylmethyl)-1H-imidazo[4,5-c]quinoline-2,4-diamine

-   1-{4-amino-2-[methyl(propyl)amino]-1H-imidazo[4,5-c]quinolin-1-yl}-2-methylpropan-2-ol

-   1-[4-amino-2-(propylamino)-1H-imidazo[4,5-c]quinolin-1-yl]-2-methylpropan-2-ol

-   N4,N4-dibenzyl-1-(2-methoxy-2-methylpropyl)-N2-propyl-1H-imidazo[4,5-c]quinoline-2,4-diamine.    -   Saponins [chapter 22 of ref. 131], which are a heterologous        group of sterol glycosides and triterpenoid glycosides that are        found in the bark, leaves, stems, roots and even flowers of a        wide range of plant species. Saponin from the bark of the        Quillaia saponaria Molina tree have been widely studied as        adjuvants. Saponin can also be commercially obtained from Smilax        ornata (sarsaprilla), Gypsophilla paniculata (brides veil), and        Saponaria officianalis (soap root). Saponin adjuvant        formulations include purified formulations, such as QS21, as        well as lipid formulations, such as ISCOMs. QS21 is marketed as        Stimulon™. Saponin compositions have been purified using HPLC        and RP-HPLC. Specific purified fractions using these techniques        have been identified, including QS7, QS17, QS18, QS21, QH-A,        QH-B and QH-C. Preferably, the saponin is QS21. A method of        production of QS21 is disclosed in ref 90. Saponin formulations        may also comprise a sterol, such as cholesterol [91].        Combinations of saponins and cholesterols can be used to form        unique particles called immunostimulating complexs (ISCOMs)        [chapter 23 of ref 131]. ISCOMs typically also include a        phospholipid such as phosphatidylethanolamine or        phosphatidylcholine. Any known saponin can be used in ISCOMs.        Preferably, the ISCOM includes one or more of Qui1A, QHA & QHC.        ISCOMs are further described in refs. 91-93. Optionally, the        ISCOMS may be devoid of additional detergent [94]. A review of        the development of saponin based adjuvants can be found in refs.        95 & 96.    -   Bacterial ADP-ribosylating toxins (e.g. the E. coli heat labile        enterotoxin “LT”, cholera toxin “CT”, or pertussis toxin “PT”)        and detoxified derivatives thereof, such as the mutant toxins        known as LT-K63 and LT-R72 [97]. The use of detoxified        ADP-ribosylating toxins as mucosal adjuvants is described in        ref. 98 and as parenteral adjuvants in ref 99.    -   Bioadhesives and mucoadhesives, such as esterified hyaluronic        acid microspheres [100] or chitosan and its derivatives [101].    -   Microparticles (i.e. a particle of ˜100 nm to ˜150 μm in        diameter, more preferably ˜200 nm to ˜30 μm in diameter, or ˜500        nm to ˜10 μm in diameter) formed from materials that are        biodegradable and non-toxic (e.g. a poly(α-hydroxy acid), a        polyhydroxybutyric acid, a polyorthoester, a polyanhydride, a        polycaprolactone, etc.), with poly(lactide-co-glycolide) being        preferred, optionally treated to have a negatively-charged        surface (e.g. with SDS) or a positively-charged surface (e.g.        with a cationic detergent, such as CTAB).    -   Liposomes (Chapters 13 & 14 of ref. 131). Examples of liposome        formulations suitable for use as adjuvants are described in        refs. 102-104.    -   Polyoxyethylene ethers and polyoxyethylene esters [105]. Such        formulations further include polyoxyethylene sorbitan ester        surfactants in combination with an octoxynol [106] as well as        polyoxyethylene alkyl ethers or ester surfactants in combination        with at least one additional non-ionic surfactant such as an        octoxynol [107]. Preferred polyoxyethylene ethers are selected        from the following group: polyoxyethylene-9-lauryl ether        (laureth 9), polyoxyethylene-9-steoryl ether,        polyoxytheylene-8-steoryl ether, polyoxyethylene-4-lauryl ether,        polyoxyethylene-35-lauryl ether, and polyoxyethylene-23-lauryl        ether.    -   Muramyl peptides, such as        N-acetylmuramyl-L-threonyl-D-isoglutamine (“thr-MDP”),        N-acetyl-normuramyl-L-alanyl-D-isoglutamine (nor-MDP),        N-acetylglucsaminyl-N-acetylmuramyl-L-Al-D-isoglu-L-Ala-dipalmitoxy        propylamide (“DTP-DPP”, or “Theramide™),        N-acetylmuramyl-L-alanyl-D-isoglutaminyl-L-alanine-2-(1′-2′dipalmitoyl-sn-glycero-3-hydroxyphosphoryloxy)-ethylamine        (“MTP-PE”).    -   An outer membrane protein proteosome preparation prepared from a        first Gram-negative bacterium in combination with a        liposaccharide (LPS) preparation derived from a second        Gram-negative bacterium, wherein the outer membrane protein        proteosome and LPS preparations form a stable non-covalent        adjuvant complex. Such complexes include “IVX-908”, a complex        comprised of Neisseria meningitidis outer membrane and LPS. They        have been used as adjuvants for influenza vaccines [108].    -   A polyoxidonium polymer [109, 110] or other N-oxidized        polyethylene-piperazine derivative.    -   Methyl inosine 5′-monophosphate (“MIMP”) [111].    -   A polyhydroxlated pyrrolizidine compound [112], such as one        having formula:

-   -    where R is selected from the group comprising hydrogen,        straight or branched, unsubstituted or substituted, saturated or        unsaturated acyl, alkyl (e.g. cycloalkyl), alkenyl, alkynyl and        aryl groups, or a pharmaceutically acceptable salt or derivative        thereof. Examples include, but are not limited to: casuarine,        casuarine-6-α-D-glucopyranose, 3-epi-casuarine, 7-epi-casuarine,        3,7-diepi-casuarine, etc.    -   A CD1d ligand, such as an α-glycosylceramide [113-120] (e.g.        α-galactosylceramide), phytosphingosine-containing        α-glycosylceramides, OCH, KRN7000        [(2S,3S,4R)-1-O-(α-D-galactopyranosyl)-2-(N-hexacosanoylamino)-1,3,4-octadecanetriol],        CRONY-101, 3″-O-sulfo-galactosylceramide, etc.    -   A gamma inulin [121] or derivative thereof, such as algammulin.    -   A compound of formula I, II or III, or a salt thereof:

-   -    as defined in reference 122, such as ‘ER 803058’, ‘ER 803732’,        ‘ER 804053’, ER 804058’, ‘ER 804059’, ‘ER 804442’, ‘ER 804680’,        ‘ER 804764’, ER 803022 or ‘ER 804057’ e.g.:

-   -   Derivatives of lipid A from Escherichia coli such as OM-174        (described in refs. 123 & 124).    -   A formulation of a cationic lipid and a (usually neutral)        co-lipid, such as        aminopropyl-dimethyl-myristoleyloxy-propanaminium        bromide-diphytanoylphosphatidyl-ethanolamine (“Vaxfectin™”) or        aminopropyl-dimethyl-bis-dodecyloxy-propanaminium        bromide-dioleoylphosphatidyl-ethanolamine (“GAP-DLRIE:DOPE”).        Formulations containing        (±)—N-(3-aminopropyl)-N,N-dimethyl-2,3-bis(syn-9-tetradeceneyloxy)-1-propanaminium        salts are preferred [125].    -   Compounds containing lipids linked to a phosphate-containing        acyclic backbone, such as the TLR4 antagonist E5564 [126, 127]:

These and other adjuvant-active substances are discussed in more detailin references 131 & 132.

The adjuvant(s) for use in the present invention may be modulatorsand/or agonists of Toll-Like Receptors (TLR). For example, they may beagonists of one or more of the human TLR1, TLR2, TLR3, TLR4, TLR7, TLR8,and/or TLR9 proteins. Preferred agents are agonists of TLR7 (e.g.imidazoquinolines) and/or TLR9 (e.g. CpG oligonucleotides). These agentsare useful for activating innate immunity pathways.

A single vaccine may include two or more of said adjuvants.

Antigens and adjuvants in a composition will typically be in admixture.

Aluminum Salt Adjuvants

The adjuvants known as aluminum hydroxide and aluminum phosphate may beused. These names are conventional, but are used for convenience only,as neither is a precise description of the actual chemical compoundwhich is present (e.g. see chapter 9 of reference 131). The inventioncan use any of the “hydroxide” or “phosphate” adjuvants that are ingeneral use as adjuvants.

The adjuvants known as “aluminium hydroxide” are typically aluminiumoxyhydroxide salts, which are usually at least partially crystalline.Aluminium oxyhydroxide, which can be represented by the formula AlO(OH),can be distinguished from other aluminium compounds, such as aluminiumhydroxide Al(OH)₃, by infrared (IR) spectroscopy, in particular by thepresence of an adsorption band at 1070 cm⁻¹ and a strong shoulder at3090-3100 cm⁻¹ [chapter 9 of ref. 131]. The degree of crystallinity ofan aluminium hydroxide adjuvant is reflected by the width of thediffraction band at half height (WHH), with poorly-crystalline particlesshowing greater line broadening due to smaller crystallite sizes. Thesurface area increases as WHH increases, and adjuvants with higher WHHvalues have been seen to have greater capacity for antigen adsorption. Afibrous morphology (e.g. as seen in transmission electron micrographs)is typical for aluminium hydroxide adjuvants. The pI of aluminiumhydroxide adjuvants is typically about 11 i.e. the adjuvant itself has apositive surface charge at physiological pH. Adsorptive capacities ofbetween 1.8-2.6 mg protein per mg Al⁺⁺⁺ at pH 7.4 have been reported foraluminium hydroxide adjuvants.

The adjuvants known as “aluminium phosphate” are typically aluminiumhydroxyphosphates, often also containing a small amount of sulfate (i.e.aluminium hydroxyphosphate sulfate). They may be obtained byprecipitation, and the reaction conditions and concentrations duringprecipitation influence the degree of substitution of phosphate forhydroxyl in the salt. Hydroxyphosphates generally have a PO₄/Al molarratio between 0.3 and 1.2. Hydroxyphosphates can be distinguished fromstrict AlPO₄ by the presence of hydroxyl groups. For example, an IRspectrum band at 3164 cm⁻¹ (e.g. when heated to 200° C.) indicates thepresence of structural hydroxyls [ch. 9 of ref. 131]

The PO₄/Al³⁺ molar ratio of an aluminium phosphate adjuvant willgenerally be between 0.3 and 1.2, preferably between 0.8 and 1.2, andmore preferably 0.95+0.1. The aluminium phosphate will generally beamorphous, particularly for hydroxyphosphate salts. A typical adjuvantis amorphous aluminium hydroxyphosphate with PO₄/Al molar ratio between0.84 and 0.92, included at 0.6 mg Al³⁺/ml. The aluminium phosphate willgenerally be particulate (e.g. plate-like morphology as seen intransmission electron micrographs). Typical diameters of the particlesare in the range 0.5-20 μm (e.g. about 5-10m) after any antigenadsorption. Adsorptive capacities of between 0.7-1.5 mg protein per mgAl⁺⁺⁺ at pH 7.4 have been reported for aluminium phosphate adjuvants.

The point of zero charge (PZC) of aluminium phosphate is inverselyrelated to the degree of substitution of phosphate for hydroxyl, andthis degree of substitution can vary depending on reaction conditionsand concentration of reactants used for preparing the salt byprecipitation. PZC is also altered by changing the concentration of freephosphate ions in solution (more phosphate=more acidic PZC) or by addinga buffer such as a histidine buffer (makes PZC more basic). Aluminiumphosphates used according to the invention will generally have a PZC ofbetween 4.0 and 7.0, more preferably between 5.0 and 6.5 e.g. about 5.7.

Suspensions of aluminium salts used to prepare compositions of theinvention may contain a buffer (e.g. a phosphate or a histidine or aTris buffer), but this is not always necessary. The suspensions arepreferably sterile and pyrogen-free. A suspension may include freeaqueous phosphate ions e.g. present at a concentration between 1.0 and20 mM, preferably between 5 and 15 mM, and more preferably about 10 mM.The suspensions may also comprise sodium chloride.

The invention can use a mixture of both an aluminium hydroxide and analuminium phosphate. In this case there may be more aluminium phosphatethan hydroxide e.g. a weight ratio of at least 2:1 e.g. ≧5:1, ≧6:1,≧7:1, ≧8:1, ≧9:1, etc.

The concentration of Al⁺⁺⁺ in a composition for administration to apatient is preferably less than 10 mg/ml e.g. ≦5 mg/ml, ≦4 mg/ml, ≦3mg/ml, ≦2 mg/ml, ≦1 mg/ml, etc. A preferred range is between 0.3 and 1mg/ml. A maximum of 0.85 mg/dose is preferred.

Oil-in-Water Emulsion Adjuvants

Oil-in-water emulsions have been found to be particularly suitable foruse in adjuvanting influenza virus vaccines. Various such emulsions areknown, and they typically include at least one oil and at least onesurfactant, with the oil(s) and surfactant(s) being biodegradable(metabolisable) and biocompatible. The oil droplets in the emulsion aregenerally less than 5 μm in diameter, and may even have a sub-microndiameter, with these small sizes being achieved with a microfluidiser toprovide stable emulsions. Droplets with a size less than 220 nm arepreferred as they can be subjected to filter sterilization.

The invention can be used with oils such as those from an animal (suchas fish) or vegetable source. Sources for vegetable oils include nuts,seeds and grains. Peanut oil, soybean oil, coconut oil, and olive oil,the most commonly available, exemplify the nut oils. Jojoba oil can beused e.g. obtained from the jojoba bean. Seed oils include saffloweroil, cottonseed oil, sunflower seed oil, sesame seed oil and the like.In the grain group, corn oil is the most readily available, but the oilof other cereal grains such as wheat, oats, rye, rice, teff, triticaleand the like may also be used. 6-10 carbon fatty acid esters of glyceroland 1,2-propanediol, while not occurring naturally in seed oils, may beprepared by hydrolysis, separation and esterification of the appropriatematerials starting from the nut and seed oils. Fats and oils frommammalian milk are metabolizable and may therefore be used in thepractice of this invention. The procedures for separation, purification,saponification and other means necessary for obtaining pure oils fromanimal sources are well known in the art. Most fish containmetabolizable oils which may be readily recovered. For example, codliver oil, shark liver oils, and whale oil such as spermaceti exemplifyseveral of the fish oils which may be used herein. A number of branchedchain oils are synthesized biochemically in 5-carbon isoprene units andare generally referred to as terpenoids. Shark liver oil contains abranched, unsaturated terpenoids known as squalene,2,6,10,15,19,23-hexamethyl-2,6,10,14,18,22-tetracosahexaene, which isparticularly preferred herein. Squalane, the saturated analog tosqualene, is also a preferred oil. Fish oils, including squalene andsqualane, are readily available from commercial sources or may beobtained by methods known in the art. Other preferred oils are thetocopherols (see below). Mixtures of oils can be used.

Surfactants can be classified by their ‘HLB’ (hydrophile/lipophilebalance). Preferred surfactants of the invention have a HLB of at least10, preferably at least 15, and more preferably at least 16. Theinvention can be used with surfactants including, but not limited to:the polyoxyethylene sorbitan esters surfactants (commonly referred to asthe Tweens), especially polysorbate 20 and polysorbate 80; copolymers ofethylene oxide (EO), propylene oxide (PO), and/or butylene oxide (BO),sold under the DOWFAX™ tradename, such as linear EO/PO block copolymers;octoxynols, which can vary in the number of repeatingethoxy(oxy-1,2-ethanediyl) groups, with octoxynol-9 (Triton X-100, ort-octylphenoxypolyethoxyethanol) being of particular interest;(octylphenoxy)polyethoxyethanol (IGEPAL CA-630/NP-40); phospholipidssuch as phosphatidylcholine (lecithin); nonylphenol ethoxylates, such asthe Tergitol™ NP series; polyoxyethylene fatty ethers derived fromlauryl, cetyl, stearyl and oleyl alcohols (known as Brij surfactants),such as triethyleneglycol monolauryl ether (Brij 30); and sorbitanesters (commonly known as the SPANs), such as sorbitan trioleate (Span85) and sorbitan monolaurate. Non-ionic surfactants are preferred.Preferred surfactants for including in the emulsion are Tween 80(polyoxyethylene sorbitan monooleate), Span 85 (sorbitan trioleate),lecithin and Triton X-100.

Mixtures of surfactants can be used e.g. Tween 80/Span 85 mixtures. Acombination of a polyoxyethylene sorbitan ester such as polyoxyethylenesorbitan monooleate (Tween 80) and an octoxynol such ast-octylphenoxypolyethoxyethanol (Triton X-100) is also suitable. Anotheruseful combination comprises laureth 9 plus a polyoxyethylene sorbitanester and/or an octoxynol.

Preferred amounts of surfactants (% by weight) are: polyoxyethylenesorbitan esters (such as Tween 80) 0.01 to 1%, in particular about 0.1%;octyl- or nonylphenoxy polyoxyethanols (such as Triton X-100, or otherdetergents in the Triton series) 0.001 to 0.1%, in particular 0.005 to0.02%; polyoxyethylene ethers (such as laureth 9) 0.1 to 20%, preferably0.1 to 10% and in particular 0.1 to 1% or about 0.5%.

Specific oil-in-water emulsion adjuvants useful with the inventioninclude, but are not limited to:

-   -   A submicron emulsion of squalene, Tween 80, and Span 85. The        composition of the emulsion by volume can be about 5% squalene,        about 0.5% polysorbate 80 and about 0.5% Span 85. In weight        terms, these ratios become 4.3% squalene, 0.5% polysorbate 80        and 0.48% Span 85. This adjuvant is known as ‘MF59’ [128-130],        as described in more detail in Chapter 10 of ref. 131 and        chapter 12 of ref. 132. The MF59 emulsion advantageously        includes citrate ions e.g. 10 mM sodium citrate buffer.    -   An emulsion of squalene, a tocopherol, and Tween 80. The        emulsion may include phosphate buffered saline. It may also        include Span 85 (e.g. at 1%) and/or lecithin. These emulsions        may have from 2 to 10% squalene, from 2 to 10% tocopherol and        from 0.3 to 3% Tween 80, and the weight ratio of        squalene:tocopherol is preferably ≦1 as this provides a more        stable emulsion. Squalene and Tween 80 may be present volume        ratio of about 5:2. One such emulsion can be made by dissolving        Tween 80 in PBS to give a 2% solution, then mixing 90 ml of this        solution with a mixture of (5 g of DL-α-tocopherol and 5 ml        squalene), then microfluidising the mixture. The resulting        emulsion may have submicron oil droplets e.g. with an average        diameter of between 100 and 250 nm, preferably about 180 nm.    -   An emulsion of squalene, a tocopherol, and a Triton detergent        (e.g. Triton X-100). The emulsion may also include a 3d-MPL (see        below). The emulsion may contain a phosphate buffer.    -   An emulsion comprising a polysorbate (e.g. polysorbate 80), a        Triton detergent (e.g. Triton X-100) and a tocopherol (e.g. an        α-tocopherol succinate). The emulsion may include these three        components at a mass ratio of about 75:11:10 (e.g. 750 μg/ml        polysorbate 80, 110 μg/ml Triton X-100 and 100 μg/ml        α-tocopherol succinate), and these concentrations should include        any contribution of these components from antigens. The emulsion        may also include squalene. The emulsion may also include a        3d-MPL (see below). The aqueous phase may contain a phosphate        buffer.    -   An emulsion of squalane, polysorbate 80 and poloxamer 401        (“Pluronic™ L121”). The emulsion can be formulated in phosphate        buffered saline, pH 7.4. This emulsion is a useful delivery        vehicle for muramyl dipeptides, and has been used with        threonyl-MDP in the “SAF-1” adjuvant [133] (0.05-1% Thr-MDP, 5%        squalane, 2.5% Pluronic L121 and 0.2% polysorbate 80). It can        also be used without the Thr-MDP, as in the “AF” adjuvant [134]        (5% squalane, 1.25% Pluronic L121 and 0.2% polysorbate 80).        Microfluidisation is preferred.    -   An emulsion comprising squalene, an aqueous solvent, a        polyoxyethylene alkyl ether hydrophilic nonionic surfactant        (e.g. polyoxyethylene (12) cetostearyl ether) and a hydrophobic        nonionic surfactant (e.g. a sorbitan ester or mannide ester,        such as sorbitan monoleate or ‘Span 80’). The emulsion is        preferably thermoreversible and/or has at least 90% of the oil        droplets (by volume) with a size less than 200 nm [135]. The        emulsion may also include one or more of alditol; a        cryoprotective agent (e.g. a sugar, such as dodecylmaltoside        and/or sucrose); and/or an alkylpolyglycoside. Such emulsions        may be lyophilized.    -   An emulsion having from 0.5-50% of an oil, 0.1-10% of a        phospholipid, and 0.05-5% of a non-ionic surfactant. As        described in reference 136, preferred phospholipid components        are phosphatidylcholine, phosphatidylethanolamine,        phosphatidylserine, phosphatidylinositol, phosphatidylglycerol,        phosphatidic acid, sphingomyelin and cardiolipin. Submicron        droplet sizes are advantageous.    -   A submicron oil-in-water emulsion of a non-metabolisable oil        (such as light mineral oil) and at least one surfactant (such as        lecithin, Tween 80 or Span 80). Additives may be included, such        as Qui1A saponin, cholesterol, a saponin-lipophile conjugate        (such as GPI-0100, described in reference 137, produced by        addition of aliphatic amine to desacylsaponin via the carboxyl        group of glucuronic acid), dimethyldioctadecylammonium bromide        and/or N,N-dioctadecyl-N,N-bis(2-hydroxyethyl)propanediamine.    -   An emulsion in which a saponin (e.g. Qui1A or QS21) and a sterol        (e.g. a cholesterol) are associated as helical micelles [138].    -   An emulsion comprising a mineral oil, a non-ionic lipophilic        ethoxylated fatty alcohol, and a non-ionic hydrophilic        surfactant (e.g. an ethoxylated fatty alcohol and/or        polyoxyethylene-polyoxypropylene block copolymer) [139].    -   An emulsion comprising a mineral oil, a non-ionic hydrophilic        ethoxylated fatty alcohol, and a non-ionic lipophilic surfactant        (e.g. an ethoxylated fatty alcohol and/or        polyoxyethylene-polyoxypropylene block copolymer) [139].

The emulsions may be mixed with antigen extemporaneously, at the time ofdelivery. Thus the adjuvant and antigen may be kept separately in apackaged or distributed vaccine, ready for final formulation at the timeof use. The antigen will generally be in an aqueous form, such that thevaccine is finally prepared by mixing two liquids. The volume ratio ofthe two liquids for mixing can vary (e.g. between 5:1 and 1:5) but isgenerally about 1:1.

After the antigen and adjuvant have been mixed, haemagglutinin antigenwill generally remain in aqueous solution but may distribute itselfaround the oil/water interface. In general, little if any haemagglutininwill enter the oil phase of the emulsion.

Where a composition includes a tocopherol, any of the α, β, γ, δ, ε or ξtocopherols can be used, but α-tocopherols are preferred. The tocopherolcan take several forms e.g. different salts and/or isomers. Saltsinclude organic salts, such as succinate, acetate, nicotinate, etc.D-α-tocopherol and DL-α-tocopherol can both be used. Tocopherols areadvantageously included in vaccines for use in elderly patients (e.g.aged 60 years or older) because vitamin E has been reported to have apositive effect on the immune response in this patient group [140]. Theyalso have antioxidant properties that may help to stabilize theemulsions [141]. A preferred α-tocopherol is DL-α-tocopherol, and thepreferred salt of this tocopherol is the succinate. The succinate salthas been found to cooperate with TNF-related ligands in vivo. Moreover,α-tocopherol succinate is known to be compatible with influenza vaccinesand to be a useful preservative as an alternative to mercurial compounds[10].

Immunostimulatory Oligonucleotides

Immunostimulatory oligonucleotides can include nucleotidemodifications/analogs such as phosphorothioate modifications and can bedouble-stranded or (except for RNA) single-stranded. References 142, 143and 144 disclose possible analog substitutions e.g. replacement ofguanosine with T-deoxy-7-deazaguanosine. The adjuvant effect of CpGoligonucleotides is further discussed in refs. 145-150. A CpG sequencemay be directed to TLR9, such as the motif GTCGTT or TTCGTT [151]. TheCpG sequence may be specific for inducing a Th1 immune response, such asa CpG-A ODN (oligodeoxynucleotide), or it may be more specific forinducing a B cell response, such a CpG-B ODN. CpG-A and CpG-B ODNs arediscussed in refs. 152-154. Preferably, the CpG is a CpG-A ODN.Preferably, the CpG oligonucleotide is constructed so that the 5′ end isaccessible for receptor recognition. Optionally, two CpG oligonucleotidesequences may be attached at their 3′ ends to form “immunomers”. See,for example, references 151 & 155-157. A useful CpG adjuvant is CpG7909,also known as ProMune™ (Coley Pharmaceutical Group, Inc.).

As an alternative, or in addition, to using CpG sequences, TpG sequencescan be used [158]. These oligonucleotides may be free from unmethylatedCpG motifs.

The immunostimulatory oligonucleotide may be pyrimidine-rich. Forexample, it may comprise more than one consecutive thymidine nucleotide(e.g. TTTT, as disclosed in ref. 158), and/or it may have a nucleotidecomposition with >25% thymidine (e.g. >35%, >40%, >50%, >60%, >80%,etc.). For example, it may comprise more than one consecutive cytosinenucleotide (e.g. CCCC, as disclosed in ref. 158), and/or it may have anucleotide composition with >25% cytosine(e.g. >35%, >40%, >50%, >60%, >80%, etc.). These oligonucleotides may befree from unmethylated CpG motifs.

Immunostimulatory oligonucleotides will typically comprise at least 20nucleotides. They may comprise fewer than 100 nucleotides.

3 de-O-acylated monophosphoryl Lipid A

3dMPL (also known as 3 de-O-acylated monophosphoryl lipid A or3-O-desacyl-4′-monophosphoryl lipid A) is an adjuvant in which position3 of the reducing end glucosamine in monophosphoryl lipid A has beende-acylated. 3dMPL has been prepared from a heptoseless mutant ofSalmonella minnesota, and is chemically similar to lipid A but lacks anacid-labile phosphoryl group and a base-labile acyl group. It activatescells of the monocyte/macrophage lineage and stimulates release ofseveral cytokines, including IL-1, IL-12, TNF-α and GM-CSF (see alsoref. 159). Preparation of 3dMPL was originally described in reference160.

3dMPL can take the form of a mixture of related molecules, varying bytheir acylation (e.g. having 3, 4, 5 or 6 acyl chains, which may be ofdifferent lengths). The two glucosamine (also known as2-deoxy-2-amino-glucose) monosaccharides are N-acylated at their2-position carbons (i.e. at positions 2 and 2′), and there is alsoO-acylation at the 3′ position. The group attached to carbon 2 hasformula —NH—CO—CH₂—CR¹R¹′. The group attached to carbon 2′ has formula—NH—CO—CH₂—CR²R²′. The group attached to carbon 3′ has formula—O—CO—CH₂—CR³R³′. A representative structure is:

Groups R¹, R² and R³ are each independently —(CH₂)—CH₃. The value of nis preferably between 8 and 16, more preferably between 9 and 12, and ismost preferably 10.

Groups R¹′, R²′ and R³′ can each independently be: (a) —H; (b) —OH; or(c) —O—CO—R⁴,where R⁴ is either —H or —(CH₂)_(m)—CH₃, wherein the valueof m is preferably between 8 and 16, and is more preferably 10, 12 or14. At the 2 position, in is preferably 14. At the 2′ position, in ispreferably 10. At the 3′ position, in is preferably 12. Groups R¹′, R²′and R³′ are thus preferably —O-acyl groups from dodecanoic acid,tetradecanoic acid or hexadecanoic acid.

When all of R¹′, R²′ and R³′ are —H then the 3dMPL has only 3 acylchains (one on each of positions 2, 2′ and 3′). When only two of R¹′,R²′ and R³′ are —H then the 3dMPL can have 4 acyl chains. When only oneof R¹′, R²′ and R³′ is —H then the 3dMPL can have 5 acyl chains. Whennone of R¹′, R²′ and R³′ is —H then the 3dMPL can have 6 acyl chains.The 3dMPL adjuvant used according to the invention can be a mixture ofthese forms, with from 3 to 6 acyl chains, but it is preferred toinclude 3dMPL with 6 acyl chains in the mixture, and in particular toensure that the hexaacyl chain form makes up at least 10% by weight ofthe total 3dMPL e.g. ≧20%, ≧30%, ≧40%, ≧50% or more. 3dMPL with 6 acylchains has been found to be the most adjuvant-active form.

Thus the most preferred form of 3dMPL for inclusion in compositions ofthe invention is:

Where 3dMPL is used in the form of a mixture then references to amountsor concentrations of 3dMPL in compositions of the invention refer to thecombined 3dMPL species in the mixture.

In aqueous conditions, 3dMPL can form micellar aggregates or particleswith different sizes e.g. with a diameter <150 nm or >500 nm. Either orboth of these can be used with the invention, and the better particlescan be selected by routine assay. Smaller particles (e.g. small enoughto give a clear aqueous suspension of 3dMPL) are preferred for useaccording to the invention because of their superior activity [161].Preferred particles have a mean diameter less than 220 nm, morepreferably less than 200 nm or less than 150 nm or less than 120 nm, andcan even have a mean diameter less than 100 nm. In most cases, however,the mean diameter will not be lower than 50 nm. These particles aresmall enough to be suitable for filter sterilization. Particle diametercan be assessed by the routine technique of dynamic light scattering,which reveals a mean particle diameter. Where a particle is said to havea diameter of x nm, there will generally be a distribution of particlesabout this mean, but at least 50% by number (e.g. ≧60%, ≧70%, ≧80%,≧90%, or more) of the particles will have a diameter within the rangex±25%.

3dMPL can advantageously be used in combination with an oil-in-wateremulsion. Substantially all of the 3dMPL may be located in the aqueousphase of the emulsion.

The 3dMPL can be used on its own, or in combination with one or morefurther compounds. For example, it is known to use 3dMPL in combinationwith the QS21 saponin [162] (including in an oil-in-water emulsion[163]), with an immunostimulatory oligonucleotide, with both QS21 and animmunostimulatory oligonucleotide, with aluminum phosphate [164], withaluminum hydroxide [165], or with both aluminum phosphate and aluminumhydroxide.

Preferred Adjuvanting Regimens

Dosing regimens of the invention involve an initial administration of anadjuvanted influenza vaccine. Preferred adjuvants for use in thisinitial vaccine are oil-in-water emulsions.

The second dose of a 2-dose regimen is preferably unadjuvanted. As analternative, it may be adjuvanted, but with a different adjuvant fromthe first dose. Where the first dose is adjuvanted with an oil-in-wateremulsion, a preferred adjuvant for use with an adjuvanted second dosecomprises an aluminium salt.

Pharmaceutical Compositions

Compositions of the invention are pharmaceutically acceptable and aretypically in aqueous form. They may include components in addition tothe antigen (and, where applicable, the adjuvant) e.g. they typicallyinclude one or more pharmaceutical carrier(s) and/or excipient(s). Athorough discussion of such components is available in reference 166.

The composition may include preservatives such as thiomersal or2-phenoxyethanol. It is preferred, however, that the vaccine should besubstantially free from (i.e. less than 5 μg/ml) mercurial material e.g.thiomersal-free [10, 167]. Vaccines containing no mercury are morepreferred. Preservative-free vaccines are particularly preferred.

To control tonicity, it is preferred to include a physiological salt,such as a sodium salt. Sodium chloride (NaCl) is preferred, which may bepresent at between 1 and 20 mg/ml. Other salts that may be presentinclude potassium chloride, potassium dihydrogen phosphate, disodiumphosphate dehydrate, magnesium chloride, calcium chloride, etc.

Compositions will generally have an osmolality of between 200 mOsm/kgand 400 mOsm/kg, preferably between 240-360 mOsm/kg, and will morepreferably fall within the range of 290-310 mOsm/kg. Osmolality haspreviously been reported not to have an impact on pain caused byvaccination [168], but keeping osmolality in this range is neverthelesspreferred.

Compositions may include one or more buffers. Typical buffers include: aphosphate buffer; a Tris buffer; a borate buffer; a succinate buffer; ahistidine buffer (particularly with an aluminum hydroxide adjuvant); ora citrate buffer. Buffers will typically be included in the 5-20 mMrange.

The pH of a composition will generally be between 5.0 and 8.1, and moretypically between 6.0 and 8.0 e.g. between 6.5 and 7.5, between 7.0 and7.8. A process of the invention may therefore include a step ofadjusting the pH of the bulk vaccine prior to packaging.

The composition is preferably sterile. The composition is preferablynon-pyrogenic e.g. containing <1 EU (endotoxin unit, a standard measure)per dose, and preferably <0.1 EU per dose. The composition is preferablygluten free.

The composition may include material for a single immunisation, or mayinclude material for multiple immunisations (i.e. a ‘multidose’ kit).The inclusion of a preservative is preferred in multidose arrangements.As an alternative (or in addition) to including a preservative inmultidose compositions, the compositions may be contained in a containerhaving an aseptic adaptor for removal of material.

Influenza vaccines are typically administered in a dosage volume ofabout 0.5 ml, although a half dose (i.e. about 0.25 ml) may beadministered to children (e.g. up to 36 months of age).

Compositions and kits are preferably stored at between 2° C. and 8° C.They should not be frozen. They should ideally be kept out of directlight.

Kits of the Invention

The invention includes kits of the first and further influenza vaccines.One kit component will be a first adjuvanted vaccine, and another kitcomponent will be a further vaccine, optionally adjuvanted. The twocomponents will be kept separately, as they are administered to apatient at substantially different times.

Each individual vaccine in a kit may be ready for use, or may be readyfor extemporaneous preparation at the time of delivery. Thisextemporaneous arrangement allows the adjuvant and the antigen to bekept separately until the time of use, which is particularly useful whenusing an oil-in-water emulsion adjuvant.

Where a vaccine is prepared extemporaneously, its components arephysically separate from each other within the kit, and this separationcan be achieved in various ways. For instance, the two components may bein two separate containers, such as vials. The contents of the two vialscan then be mixed e.g. by removing the contents of one vial and addingthem to the other vial, or by separately removing the contents of bothvials and mixing them in a third container. In a preferred arrangement,one of the kit components is in a syringe and the other is in acontainer such as a vial. The syringe can be used (e.g. with a needle)to insert its contents into the second container for mixing, and themixture can then be withdrawn into the syringe. The mixed contents ofthe syringe can then be administered to a patient, typically through anew sterile needle. Packing one component in a syringe eliminates theneed for using a separate syringe for patient administration.

In another preferred arrangement, the two components of a vaccine areheld together but separately in the same syringe e.g. a dual-chambersyringe, such as those disclosed in references 169-176 etc. When thesyringe is actuated (e.g. during administration to a patient) then thecontents of the two chambers are mixed. This arrangement avoids the needfor a separate mixing step at the time of use.

Where a vaccine is prepared extemporaneously, its components willgenerally be in aqueous form. In some arrangements, a component(typically the antigen component rather than the adjuvant component) isin dry form (e.g. in a lyophilised form), with the other component beingin aqueous form. The two components can be mixed in order to reactivatethe dry component and give an aqueous composition for administration toa patient. A lyophilised component will typically be located within avial rather than a syringe. Dried components may include stabilizerssuch as lactose, sucrose or mannitol, as well as mixtures thereof e.g.lactose/sucrose mixtures, sucrose/mannitol mixtures, etc. One possiblearrangement uses an aqueous adjuvant component in a pre-filled syringeand a lyophilised antigen component in a vial.

Packaging of Compositions or Kit Components

Suitable containers for compositions of the invention (or kitcomponents) include vials, syringes (e.g. disposable syringes), nasalsprays, etc. These containers should be sterile.

Where a composition/component is located in a vial, the vial ispreferably made of a glass or plastic material. The vial is preferablysterilized before the composition is added to it. To avoid problems withlatex-sensitive patients, vials are preferably sealed with a latex-freestopper, and the absence of latex in all packaging material ispreferred. The vial may include a single dose of vaccine, or it mayinclude more than one dose (a ‘multidose’ vial) e.g. 10 doses. Preferredvials are made of colorless glass.

A vial can have a cap (e.g. a Luer lock) adapted such that a pre-filledsyringe can be inserted into the cap, the contents of the syringe can beexpelled into the vial (e.g. to reconstitute lyophilised materialtherein), and the contents of the vial can be removed back into thesyringe. After removal of the syringe from the vial, a needle can thenbe attached and the composition can be administered to a patient. Thecap is preferably located inside a seal or cover, such that the seal orcover has to be removed before the cap can be accessed. A vial may havea cap that permits aseptic removal of its contents, particularly formultidose vials.

Where a composition/component is packaged into a syringe, the syringemay have a needle attached to it. If a needle is not attached, aseparate needle may be supplied with the syringe for assembly and use.Such a needle may be sheathed. Safety needles are preferred. 1-inch23-gauge, 1-inch 25-gauge and ⅝-inch 25-gauge needles are typical.Syringes may be provided with peel-off labels on which the lot number,influenza season and expiration date of the contents may be printed, tofacilitate record keeping. The plunger in the syringe preferably has astopper to prevent the plunger from being accidentally removed duringaspiration. The syringes may have a latex rubber cap and/or plunger.Disposable syringes contain a single dose of vaccine. The syringe willgenerally have a tip cap to seal the tip prior to attachment of aneedle, and the tip cap is preferably made of a butyl rubber. If thesyringe and needle are packaged separately then the needle is preferablyfitted with a butyl rubber shield. Preferred syringes are those marketedunder the trade name “Tip-Lok”™.

Containers may be marked to show a half-dose volume e.g. to facilitatedelivery to children. For instance, a syringe containing a 0.5 ml dosemay have a mark showing a 0.25 ml volume.

Where a glass container (e.g. a syringe or a vial) is used, then it ispreferred to use a container made from a borosilicate glass rather thanfrom a soda lime glass.

A kit or composition may be packaged (e.g. in the same box) with aleaflet including details of the vaccine e.g. instructions foradministration, details of the antigens within the vaccine, etc. Theinstructions may also contain warnings e.g. to keep a solution ofadrenaline readily available in case of anaphylactic reaction followingvaccination, etc.

Methods of Treatment, and Administration of the Vaccine

Compositions of the invention are suitable for administration to humanpatients. The immune response raised according to the invention willgenerally include an antibody response, preferably a protective antibodyresponse. Methods for assessing antibody responses, neutralizingcapability and protection after influenza virus vaccination are wellknown in the art. Human studies have shown that antibody titers againsthemagglutinin of human influenza virus are correlated with protection (aserum sample hemagglutination-inhibition titer of about 30-40 givesaround 50% protection from infection by a homologous virus) [177].Antibody responses are typically measured by hemagglutinationinhibition, by microneutralisation, by single radial immunodiffusion(SRID), and/or by single radial hemolysis (SRH). These assay techniquesare well known in the art.

Compositions of the invention can be administered in various ways. Themost preferred immunisation route is by intramuscular injection (e.g.into the aim or leg), but other available routes include subcutaneousinjection, intranasal [178-180], oral [181], intradermal [182, 183],transcutaneous, transdermal [184], etc.

Vaccines of the invention may be used to treat both children and adults.Influenza vaccines are currently recommended for use in pediatric andadult immunisation, from the age of 6 months. Thus the patient may beless than 1 year old, 1-5 years old, 5-15 years old, 15-55 years old, orat least 55 years old. Preferred patients for receiving the vaccines arethe elderly (e.g. ≧50 years old, ≧60 years old, preferably ≧65 years),the young (e.g. ≦5 years old), hospitalized patients, healthcareworkers, armed service and military personnel, pregnant women, thechronically ill, immunodeficient patients, patients who have taken anantiviral compound (e.g. an oseltamivir or zanamivir compound; seebelow) in the 7 days prior to receiving the vaccine, people with eggallergies and people travelling abroad. The vaccines are not suitablesolely for these groups, however, and may be used more generally in apopulation. For pandemic strains, administration to all age groups ispreferred.

Preferred compositions of the invention satisfy 1, 2 or 3 of the CPMPcriteria for efficacy. In adults (18-60 years), these criteria are:(1)≧70% seroprotection; (2)≧40% seroconversion; and/or (3) a GMTincrease of ≧2.5-fold. In elderly (>60 years), these criteria are:(1)≧60% seroprotection; (2)≧30% seroconversion; and/or (3) a GMTincrease of ≧2-fold. These criteria are based on open label studies withat least 50 patients.

Treatment is by a multiple dose schedule. As mentioned above, thevarious doses will typically use the same form of antigen and share atleast one common hemagglutinin subtype. It is preferred that the dosesare either all given parenterally or all given mucosally. The doses willtypically be given by the same administration route e.g. by the sameparenteral route, such as i.m. injection.

The multiple doses will typically be administered at least 1 week apart(e.g. at least about 2 weeks, about 3 weeks, about 4 weeks, about 6weeks, about 8 weeks, about 10 weeks apart, about 12 weeks, about 16weeks apart, etc.).

Preferred dosing regimens of the invention are 2-dose regimens. Furtherdoses may be administered in subsequent influenza seasons, typically inthe usual 1-dose format, but the standard immunization in a singleseason (e.g. within a single 6 month period or 12 month period)according to the invention will involve 2 doses. Extra doses in theregimen (e.g. a 3-dose or a 4-dose regimen) are not preferred because ofthe extra antigen requirements. If a 3rd dose is included in theregimen, however, then the third dose may either be a repeat of thefirst dose, followed by the further dose, or it may be a repeat of thefurther dose e.g. an ‘adjuvanted, adjuvanted, un-adjuvanted’ regimen, oran ‘adjuvanted, un-adjuvanted, un-adjuvanted’ regimen.

Vaccines produced by the invention may be administered to patients atsubstantially the same time as (e.g. during the same medicalconsultation or visit to a healthcare professional or vaccinationcentre) other vaccines e.g. at substantially the same time as a measlesvaccine, a mumps vaccine, a rubella vaccine, a MMR vaccine, a varicellavaccine, a MMRV vaccine, a diphtheria vaccine, a tetanus vaccine, apertussis vaccine, a DTP vaccine, a conjugated H. influenzae type bvaccine, an inactivated poliovirus vaccine, a hepatitis B virus vaccine,a meningococcal conjugate vaccine (such as a tetravalent A-C—W135-Yvaccine), a respiratory syncytial virus vaccine, a pneumococcalconjugate vaccine, etc. Administration at substantially the same time asa pneumococcal vaccine or a meningococcal vaccine is particularly usefulin elderly patients.

Similarly, vaccines of the invention may be administered to patients atsubstantially the same time as (e.g. during the same medicalconsultation or visit to a healthcare professional) an antiviralcompound, and in particular an antiviral compound active againstinfluenza virus (e.g. oseltamivir and/or zanamivir). These antiviralsinclude neuraminidase inhibitors, such as a(3R,4R,5S)-4-acetylamino-5-amino-3(1-ethylpropoxy)-1-cyclohexene-1-carboxylicacid or5-(acetylamino)-4-[(aminoiminomethyl)-amino]-2,6-anhydro-3,4,5-trideoxy-D-glycero-D-galactonon-2-enonicacid, including esters thereof (e.g. the ethyl esters) and salts thereof(e.g. the phosphate salts). A preferred antiviral is(3R,4R,5S)-4-acetylamino-5-amino-3(1-ethylpropoxy)-1-cyclohexene-1-carboxylicacid, ethyl ester, phosphate (1:1), also known as oseltamivir phosphate(TAMIFLU™).

General

The term “comprising” encompasses “including” as well as “consisting”e.g. a composition “comprising” X may consist exclusively of X or mayinclude something additional e.g. X+Y.

The word “substantially” does not exclude “completely” e.g. acomposition which is “substantially free” from Y may be completely freefrom Y. Where necessary, the word “substantially” may be omitted fromthe definition of the invention.

The term “about” in relation to a numerical value x means, for example,x±10%.

Unless specifically stated, a process comprising a step of mixing two ormore components does not require any specific order of mixing. Thuscomponents can be mixed in any order. Where there are three componentsthen two components can be combined with each other, and then thecombination may be combined with the third component, etc.

Where animal (and particularly bovine) materials are used in the cultureof cells, they should be obtained from sources that are free fromtransmissible spongiform encaphalopathies (TSEs), and in particular freefrom bovine spongiform encephalopathy (BSE). Overall, it is preferred toculture cells in the total absence of animal-derived materials.

Where a compound is administered to the body as part of a compositionthen that compound may alternatively be replaced by a suitable prodrug.

Where a cell substrate is used for reassortment or reverse geneticsprocedures, it is preferably one that has been approved for use in humanvaccine production e.g. as in Ph Eur general chapter 5.2.3.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows anti-HA IgG ELISA responses in mice receiving variousinfluenza vaccines.

MODES FOR CARRYING OUT THE INVENTION

Hemagglutinin was prepared from a H5N1 strain of avian influenza and wasformulated for intramuscular injection at 0.2 μg per dose (50 μl volumeper dose). Two vaccines were prepared: the first was unadjuvanted; thesecond was adjuvanted with MF59 emulsion at a 1:1 volume ratio. Vaccineswere administered to four groups of female Balb/c mice, 8 weeks of age,at days 0 & 28. Mice were bled at days 14 and 42 and anti-HA immuneresponses were assessed by ELISA.

Results were as follows (see also FIG. 1):

Group A B C D Day 0 No adjuvant MF59 No adjuvant MF59 Day 28 No adjuvantNo adjuvant MF59 MF59 Titre (day 14)  13  313   6   271 Responders  3/1010/10  3/10 10/10 Titre (day 42) 7125 75922 42219 148831 Responders10/10 10/10 10/10 10/10

Thus the adjuvant significantly enhances the number of responders afterthe first immunization (compare groups A and B). Including adjuvant ineither or both of the doses gave an anti-HA specific antibody responsethat is significantly higher than that induced by two doses ofnon-adjuvanted vaccine (compare groups B, C & D against group A).Moreover, animals primed with an adjuvanted vaccine can be boosted by anon-adjuvanted vaccine, achieving higher titers than priming with anunadjuvanted vaccine and boosting with an adjuvanted vaccine (comparegroups B & C). Although the absolute titers were lower in group B thanin group D, the response was more than adequate. Thus stocks of anadjuvant can be maintained by using it in only the first dose in a2-dose regimen.

It will be understood that the invention has been described by way ofexample only and modifications may be made whilst remaining within thescope and spirit of the invention.

REFERENCES The Contents of which are Hereby Incorporated by Reference

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1: A method for immunizing a patient against influenza virus infection,comprising the steps of: (i) administering a dose of influenza virusvaccine comprising an inactivated influenza antigen in combination witha first adjuvant which comprises an oil-in-water emulsion; and (ii)administering a further dose of influenza virus vaccine without thatadjuvant within six months after administering the dose in step (i). 2:The method of claim 1, wherein the further dose is administered by thesame route as the first dose. 3: The method of claim 1, wherein thefurther dose is unadjuvanted. 4: The method of claim 1, wherein thefurther dose is adjuvanted with an adjuvant that is different from thefirst adjuvant. 5: A method for completing the immunization of a patientagainst influenza virus infection, wherein the patient has previouslyreceived a dose of influenza virus vaccine comprising an inactivatedinfluenza antigen in combination with a first adjuvant which comprisesan oil-in-water emulsion, and wherein the method comprises the step ofadministering to that patient a further dose of influenza virus vaccinewithout that adjuvant. 6: The method of claim 5, wherein the furtherdose is administered by the same route as the previous dose. 7: Themethod of claim 1, wherein the vaccines include hemagglutinin at lessthan 15 μg per strain per vaccine. 8: The method of claim 1, wherein theinfluenza virus vaccines include an influenza virus antigen from a H1,H2, H3, H5, H7 or H9 influenza A virus subtype. 9: The method of claim 5wherein the vaccines include hemagglutinin at less than 15 μg per strainper vaccine. 10: The method of claim 5 wherein the influenza virusvaccines include an influenza virus antigen from a H1, H2, H3, H5, H7 orH9 influenza A virus subtype.